場發射顯示器用氧化鋅低壓螢光材料之研製與其發光現象

Abstract

本論文探討以固態燒結反應法，來製作ZnO:Zn綠色螢光粉，並探討燒結過程中，混合不同計量的還原劑ZnS以及燒結的條件對螢光粉粉體形貌、粒徑大小及分布的影響。此外，螢光粉粒徑的分散性以及對其表面作蝕刻處理的影響也做一探討。適當的硫化鋅混合比例以及最佳化的燒結參數由SEM觀測以及XRD繞射角計算其晶格常數。 實驗結果顯示，氧化鋅混合5wt%硫化鋅，在1100℃下燒結一個小時為最佳的條件。燒製成的螢光粉經粒徑分散以及表面處理後，其發光亮度會增加35%。

An investigation of the synthesis by solid state reaction method and characterization of ZnO:Zn phosphor for cathodoluminescence was presented. Effects of weight percent of ZnS that is reducing material and firing temperature on shape and particle size distribution of phosphor were studied. Besides, the influence of particle size separation and surface treatment on the phosphor was also discussed. The appropriate ZnS composition and optimal firing parameters were evaluated on the basis of SEM morphology observation, XRD crystalline calculation and EPMA composition analysis. After the overall evaluation for the phosphors with various weight percents of ZnS, phosphors sintered with 5wt% ZnS at 1100℃ for 1 hr is the optimal condition. As-fabricated phosphor after particle size separation and surface treatment will increase luminescence performance about 35%. Abstract (Chinese)…………………………………………………………………...I Abstract (English)…………………………………………………………………..II Acknowledgment…………………………………………………………………...III Contents…………………………………………………………………………….IV Tables Caption……………………………………………………………………..VI Figures Caption…………………………………………………………………...VII Chapter 1 Introduction……………………………………………………………..1 Chapter 2 Literatures Review………………………………………………………4 2.1 Field emission display……………………………………………………...5 2.2 Luminescence phenomena…………………………………………………9 2.2.1 Types of luminescence……………………………………………...9 2.2.2 Energy transitions in semiconductor phosphors…………………..11 2.2.3 Luminescence mechanisms and centers…………………………..13 2.2.4 Phonon and exciton………………………………………………..14 2.2.5 Coulombic interaction……………………………………………..17 2.3 Phosphor preparation……………………………………………………..19 2.3.1 Powder or thin films……………………………………………….20 2.3.2 Synthetic methods…………………………………………………21 2.3.3 Particle size separation…………………………………………….23 2.3.4 Surface treatments…………………………………………………23 2.3.5 Particle size and shape…………………………………………….24 2.4 Zinc oxide phosphors……………………………………………………..25 2.4.1 Cathodoluminescence of ZnO phosphors…………………………26 2.4.2 Defect reaction of ZnO in a reducing atmosphere………………..27 2.5 The observer and some basic definitions…………………………………29 2.5.1 Brightness and luminance…………………………………………29 2.5.2 Efficiency………………………………………………………….29 2.5.3 Color………………………………………………………………32 Chapter 3 Experimental Procedures……………………………………………..37 3.1 ZnO:Zn phosphor powder fabrication……………………………………37 3.2 Analysis of phosphor powder…………………………………………….39 3.2.1 Morphology evaluation by SEM…………………………………..39 3.2.2 Phase identification by X-ray diffraction………………………….39 3.2.3 Particle size distribution…………………………………………...42 3.2.4 Thermal analysis…………………………………………………..42 3.3 Screening………………………………………………………………….42 3.4 Phosphor luminescence measurement……………………………………44 3.4.1 Luminescence measurement system………………………………44 3.4.2 Cathodoluminescence spectrum measurement……………………44 3.4.3 CIE color coordinates measurement………………………………46 Chapter 4 Results and Discussion………………………………………………..50 4.1 Sintering of phosphor powders…………………………………………..50 4.1.1 Crystal growth……………………………………………………..50 4.1.2 Particle size distribution…………………………………………...55 4.1.3 X-ray diffraction analysis…………………………………………58 4.1.4 Crystalline structure of ZnO:Zn phosphors……………………….64 4.2 Cathodoluminescence property of ZnO phosphors……………………….65 4.2.1 Brightness of as-fabricated phosphors……………………………68 4.2.2 Spectrum measurement……………………………………………69 4.2.3 Color coordinate evaluation……………………………………….78 4.2.4 Optical and electrical properties of phosphors…………………….80 4.2.5 Other properties of phosphors……………………………………..84 4.3 Surface treatment…………………………………………………………86 4.4 Particle size separation……………………………………………………95 4.5 Hall measurement………………………………………………………...97 Chapter 5 Conclusions……………………………………………………………102 References…………………………………………………………………………103